Relationship Between Volumetric Capnography, Ventilation During Cardiopulmonary Resuscitation and Return of Spontaneus Circulation in an Experimental Model of Pediatric Asphyxial Cardiac Arrest

Abstract

Abstract Purpose To study the relationship between volumetric capnography (VCAP) and arterial CO2 partial pressure (PCO2) during cardiopulmonary resuscitation (CPR) and to analyze the ability of these parameters to predict the return of spontaneous circulation (ROSC) in a pediatric animal model of asphyxial cardiac arrest (CA). Methods Secondary analysis of a randomized study. Asphyxial CA was induced by muscle relaxation and extubation. CPR was started two minutes after CA occurred. Airway management was performed with early endotracheal intubation or bag-mask ventilation, according to randomization group. CPR was continued until ROSC or 24 minutes of resuscitation. End-tidal carbon dioxide (EtCO2), CO2 production (VCO2), and EtCO2/VCO2/kg ratio were continuously recorded. Results Seventy-nine piglets were included, 26 (32.9%) of whom achieved ROSC. EtCO2 was the best predictor of ROSC (AUC 0.72, p < 0.01 and optimal cutoff point of 21.6 mmHg). No statistical differences were obtained regarding VCO2, VCO2/kg and EtCO2/VCO2/kg ratios. VCO2 and VCO2/kg showed an inverse correlation with PCO2, with higher a correlation coefficient as resuscitation progressed. EtCO2 also had an inverse correlation with PCO2 from minute 18 to 24 of resuscitation. Conclusion Our findings suggest that EtCO2 is the best VCAP-derived parameter for predicting ROSC. EtCO2 and VCO2 showed an inverse correlation with PCO2. Therefore, these parameters are not adequate to measure ventilation during CPR.